a(n) = 64*n^6 - 80*n^4 + 24*n^2 - 1.

Terms

a(0) =-1a(1) =7a(2) =2911a(3) =40391a(4) =242047a(5) =950599a(6) =2883167a(7) =7338631a(8) =16451071a(9) =33489287a(10) =63202399a(11) =112211527a(12) =189447551a(13) =306634951a(14) =478821727a(15) =724955399a(16) =1068505087a(17) =1538129671a(18) =2168392031a(19) =3000519367a(20) =4083209599a(21) =5473483847a(22) =7237584991a(23) =9451922311a(24) =12204062207a(25) =15593764999